$background_color = rgba(255,255,255,0.9) //定义一个变量，后面可以直接用这个变量

html
  box-sizing border-box
  min-height 100vh
  display flex
  flex-direction column
  justify-content center
  align-items center
  text-align center
  background url('http://wes.io/hx9M/oh-la-la.jpg') center no-repeat
  background-size cover

*
  box-sizing border-box

.wrapper
  padding 20px
  min-width 350px
  background $background_color
  box-shadow 0 0 0px 10px rgba(0, 0, 0, 0.1)
  h2
    text-align center
    margin 0
    font-weight 200

.plates
  margin 0
  padding 0
  text-align left
  list-style none
  li
    border-bottom 1px solid rgba(0, 0, 0, 0.2)
    padding 10px 0px
    display flex
  label
    flex 1
    cursor pointer
  input
    display none
    
.add-items
  margin-top 20px
  input
    padding 10px
    outline 0
    border 1px solid rgba(0,0,0,0.1)